Intel's has pulled back the proverbial curtain on their second-generation Core processors, which were previously known by the codename "Sandy Bridge." Our labs results are in, and the new CPUs have proven to be significantly faster than their predecessors.

The new CPUs are built on a brand new microarchiture, and boast superior integrated graphics performance and improved energy efficiency. For our tests, we looked at a pair of processors: the 3.3GHz Core i5-2500K ($216), and the 3.4GHz Core i7-2600K ($317). The second-generation Core CPUs follow a slightly different nomenclature to the Core CPUs you're likely already familiar with. The Core i3, i5, and i7 branded chips remain. The number that follows the i3, i5 or i7 -- a "2" -- indicates that the chip is a second-generation CPU, and part of the Sandy Bridge family. The three numbers following the "2" indicate the specific processor model. The two chips we reviewed are followed by a "K," indicated they are unlocked, and primed for overclocking.

For a detailed run-down of all that Sandy Bridge has to offer, be sure to check out our overview of the new features baked into the second-generation of Intel's Core processors.

Testing Sandy Bridge

For the Core i5-2500K, Intel provided the DH67BL "Bearup Lake" motherboard, which is equipped with Intel's second-generation integrated graphics on the H67 chipset. For the Core i7-2600K, we're using the DP67BG "Burrage" motherboard, sporting the performance oriented P67 chipset.

New CPUs, new chipsets, and -- much to the chagrin of serial upgraders -- new sockets. The second-generation Intel CPUs are using the LGA-1155 socket, so you'll need to pick up an entirely new motherboard if you're planning on picking up a new CPU.

Both testbeds were outfitted identically: 4GB of DDR3 RAM, a 1 TB hard drive, an AMD Radeon HD 5870 graphics card, and an optical drive for loading applications. Occasionally, the graphics card on the i5-2500K testbed was removed for comparison testing of the H67 chipset's integrated graphics. The processors were left at their stock clock speeds. All told, our testbeds would cost under $900 to assemble. A pair of machines equipped with the Sandy Bridge CPU were provided by MicroExpress and Origin, and they sported generous overclocks. Lets check out the results!

Performance: WorldBench 6

First up is PCWorld's WorldBench 6 benchmark suite. For the uninitiated: WorldBench consists of a series of tests using real world applications to gauge a PC's performance. A series of applications run, simulating a typical workload. A WorldBench score is then compiled based on how long it took the machine to complete tasks. The results on our reference boards are impressive: Our Core i7-2600k earned a WorldBench score of 156, while the Core i5-2500K earned a 150.

Let's put those numbers in perspective. Back in August we reviewed Maingear's F131, a $2000 Mainstream desktop equipped with a Core i5-655K processor, 4GB of RAM, and a 1TB hard drive. It earned a WorldBench score of 152, but only after Maingear overclocked the CPU all the way up to 4.5GHz.

MicroExpress sent over theMicroFlex 25B, an $850 desktop equipped with the Core i5-2500K, 4GB of RAM, and a 300GB hard drive. It was overclocked to 4.1GHz, and earned a staggering 188 on WorldBench -- a result typically reserved for the upper echelons of the Performance category, in machines that cost upwards of $2000.The top tier isn't exactly slouching, either.

Origin provided their latest Genesis, equipped with a Core i7-2600K overclocked to a blistering 5GHz. This $7000 juggernaut is packed to the gills with all of the latest and greatest hardware, and earned a 223 on WorldBench -- the highest score we've ever seen. Be sure to check back for full reviews on both machines.